Optical system for camera

ABSTRACT

Disclosed herein is an optical system for a camera. The optical system for a camera includes: a first lens having positive refractive power and a meniscus shape concave toward an image; a second lens having negative refractive power and a shape concave toward the image; a third lens having the positive refractive power and a shape convex toward an object; a fourth lens having the positive refractive power and a shape convex toward the image; and a fifth lens having the negative refractive power, a shape convex toward the object and concave to the image, and one or more inflection point provided on an image surface.

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 119 ofKorean Patent Application Serial No. 10-2012-0045609, entitled “OpticalSystem for Camera” filed on Apr. 30, 2012, which is hereby incorporatedby reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an optical system for a camera, andmore particularly, to an optical system for a camera capable of beingmanufactured in a small size in order to be mounted in a mobile deviceand implementing a high resolution.

2. Description of the Related Art

Recently, as the use of a mobile communication unit such as a mobilecommunication terminal, a personal digital assistant (PDA), and a smartphone increases and a service provided through a communicationtechnology is verified, in addition to a basic communication function,various types of additional functions have been mounted. Among them, themounting of a camera for simple photographing has been generalized.

Further, recently, in an optical system of a camera used in a mobiledevice such as a cellular phone, the number of pixels has increased toeight million pixels or more in excess of five million pixels. Inaddition, a view angle of 70 degrees or more wider than a general viewangle of about 60 degrees has been demanded.

However, when a view angle of a lens is increased, an incident angle ofa light ray incident to a lens surface cannot but be increased, suchthat performance deterioration may be intensified even in the samemanufacturing tolerance. In addition, as a pixel size of a sensor isdecreased, a required spatial frequency is increased, such that anoptical system having a high resolution is required.

When the spatial frequency is increased and the resolution is increased,sensitivity to the manufacturing tolerance of the optical system cannotbut be increased. Therefore, the development of the optical systemhaving a high resolution and capable of decreasing the sensitivity hasbeen required.

Meanwhile, a high-pixel optical system supporting eight million pixels,which is an optical system for a camera according to the related art, ismainly configured of four sheets of lenses (having a pixel size of 1.4μm or more), wherein first and second lens of the four sheets of lensesare in charge of the entire refractive power of the optical system, andthird and fourth lenses thereof are in charge of image surface fieldcurvature and distortion to correct aberration that is not corrected bythe first and second lenses.

In addition, as the first and second lenses, a crown or flint basedglass lens is used. Particularly, the second lens has negativerefractive power and is made of the flint based glass material tocompensate for longitudinal chromatic aberration. However, it isdifficult to satisfy conditions such as miniaturization and costreduction with an optical system design considering a manufacturing costof an optical system for a mobile camera.

Particularly, due to characteristics of the optical system for a cameraapplied to the mobile device, a plastic lens is mainly used inconsideration of mass production, size, weight, and cost. Therefore, itis difficult to satisfy optical performance and compensate for chromaticaberration with a general optical system design.

RELATED ART DOCUMENT Patent Document

-   (Patent Document 1) Japanese Patent Laid-Open Publication No.    1997-211320

SUMMARY OF THE INVENTION

An object of the present invention is to provide an optical system for acamera capable of implementing a wide angle and a high resolution bysequentially disposing five sheets of lenses having differentlongitudinal chromatic aberration characteristics and improving anrelative illumination (the ratio of corner illumination to the center)by disposing an aperture stop between first and second lenses.

According to an exemplary embodiment of the present invention, there isprovided an optical system for a camera including: a first lens havingpositive refractive power and a meniscus shape concave toward an image;a second lens having negative refractive power and a shape concavetoward the image; a third lens having the positive refractive power anda shape convex toward an object; a fourth lens having the positiverefractive power and a shape convex toward the image; and a fifth lenshaving the negative refractive power, a shape convex toward the objectand concave to the image, and one or more inflection point provided onan image surface, wherein the first and second lenses include anaperture stop disposed therebetween in order to block unnecessary lightin light passing through the optical system.

The third lens may be configured of a lens having a shape in which bothsurfaces thereof are convex.

The fourth lens may be configured of a lens having a meniscus shapeconvex toward the image.

The fifth lens may be configured of a lens having a shape concave towardthe object.

The optical system for a camera may further include an optical filterprovided between the fifth lens and an image surface, wherein theoptical filter is configured of a cover glass coated with an infraredblocking filter for blocking excessive infrared rays included in lightintroduced from the outside.

The first to fifth lenses may be configured of a plastic lens and haveboth surfaces configured of an aspherical surface.

The optical system for a camera may satisfy the following ConditionalEquations 1 and 2 with respect to a radius of curvature of the thirdlens and a focal length of the entire optical system, and a focal lengthof the third lens and a focal length of the entire optical system

f3/f<2.0  [Conditional Equation 1]

R31/f<1.2  [Conditional Equation 2]

where f3 indicates a focal length of the third lens, R31 indicates aradius of curvature on a surface of the third lens L3 toward the object,and f indicates a focal length of the entire optical system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lens configuration diagram showing a lens arrangement of anoptical system for a camera according to a first exemplary embodiment ofthe present invention;

FIGS. 2A and 2B are, respectively, views showing astigmatism anddistortion of the optical system shown in Table 1 and FIG. 1;

FIG. 3 is a lens configuration diagram showing a lens arrangement of anoptical system for a camera according to a second exemplary embodimentof the present invention; and

FIGS. 4A and 4B are, respectively, views showing astigmatism anddistortion of the optical system shown in Table 3 and FIG. 3.

FIG. 5 is a lens configuration diagram showing a lens arrangement of anoptical system for a camera according to a third exemplary embodiment ofthe present invention;

FIGS. 6A and 6B are, respectively, views showing astigmatism anddistortion of the optical system shown in Table 5 and FIG. 5.

FIG. 7 is a lens configuration diagram showing a lens arrangement of anoptical system for a camera according to a fourth exemplary embodimentof the present invention;

FIGS. 8A and 8B are, respectively, views showing astigmatism anddistortion of the optical system shown in Table 7 and FIG. 7.

FIG. 9 is a lens configuration diagram showing a lens arrangement of anoptical system for a camera according to a fifth exemplary embodiment ofthe present invention;

FIGS. 10A and 10B are, respectively, views showing astigmatism anddistortion of the optical system shown in Table 9 and FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The acting effects and technical configuration with respect to theobjects of an optical system for a camera according to the presentinvention will be clearly understood by the following description inwhich exemplary embodiments of the present invention are described withreference to the accompanying drawings.

However, in the lens configuration diagrams according to the followingexemplary embodiments, a thickness, a size, and a shape of the lens areslightly exaggerated for a detailed description of the presentinvention. Particularly, a shape of a spherical surface or an asphericalsurface suggested in the lens configuration diagram is only an example.Therefore, the lens is not limited to the above-mentioned shape.

FIG. 1 is a lens configuration diagram of an optical system for a cameraaccording to a first exemplary embodiment of the present invention. Asshown in FIG. 1, the optical system for a camera according to the firstexemplary embodiment of the present invention may be configured toinclude a first lens (L1) having a meniscus shape concave toward animage and positive refractive power, a second lens L2 having a shapeconcave toward the image and negative refractive power, a third lens L3having a shape convex toward an object and the positive refractivepower, a fourth lens L4 having a shape convex toward the image and thepositive refractive power, and a fifth lens L5 having a shape convextoward the object and concave toward the image and the negativerefractive power, wherein the first to fifth lenses L1 to L5 aresequentially arranged from the object.

Here, the first and second lenses L1 and L2 may include an aperture stop(AS) installed therebetween.

In addition, the optical system for a camera may include an opticalfilter (OF) provided between the fifth lens L5 and an image surface 11,wherein the optical filter (OF) is configured of an infrared filter forblocking excessive infrared rays in light passing through the opticalsystem or a cover glass coated with the infrared filter.

In the optical system for a camera according to the exemplary embodimentof the present invention, the aperture stop (AS) is disposed at the rearof the first lens L1, that is, between the first and second lenses L1and L2, thereby making it possible to decrease sensitivity of the firstlens L1 to a tolerance. That is, in the case in which the aperture stop(AS) is disposed in front of the first lens L1, an image height isincreased due to light incident to the optical system, such that thefirst lens L1 may become sensitive to decenter. However, when theaperture stop (AS) is disposed between the first and second lenses L1and L2 as in the exemplary embodiment of the present invention, since anincident angle of light rays incident to the first lens L1 may bedecreased, the sensitivity of the first lens L1 to the manufacturingtolerance may be decreased, such that a degree of freedom in design ofthe optical system may be increased.

In addition, when the aperture stop (AS) is disposed between the firstand second lenses L1 and L2, a size of an entrance pupil imaged by thefirst lens L1 becomes larger toward an edge of the image surface,thereby making it possible to improve an ambient light amount ratio.

Meanwhile, according to the exemplary embodiment of the presentinvention, since the aperture stop (AS) is disposed between the firstand second lenses L1 and L2, an incident angle of the light ray isincreased, such that an incident angle at an image surface side of thefirst lens L1 is significantly increased, thereby making it possible toincrease the sensitivity to the manufacturing tolerance. However, thefirst lens L1 is designed in the shape concave toward the image, therebymaking it possible to decrease the incident angle of the light ray tothe first lens L1.

However, in the case in which a lens concave toward the image is used asthe first lens L1, a chromatic aberration correction function may beweakened. Since the refractive power at the image surface of the lens L1may be changed into the negative refractive power, the chromaticaberration correction function capable of being removed using adifference in dispersion property by the Abbe's number of the first andsecond lenses L1 and L2 may be weakened.

Therefore, according to the exemplary embodiment of the presentinvention, the third lens L3 is formed to be convex toward the objectand a relationship between a focal length (f3) of the third lens L3 anda radius of curvature (R31) on a surface of the third lens L3 toward theobject is used, thereby making it possible to correct longitudinalchromatic aberration. A more detailed description thereof will beprovided through the following Conditional Equations.

Here, the third lens L3 may also be configured of a lens having a shapein which both surfaces thereof are convex.

Further, in the optical system according to the exemplary embodiment ofthe present invention, the fourth lens L4 may be configured of a lenshaving a meniscus shape convex toward the image.

In addition, in the optical system according to the exemplary embodimentof the present invention, the fifth lens L5 may be configured of a lenshaving a shape concave toward the object.

Further, in the optical system according to the exemplary embodiment ofthe present invention, all of the first to fifth lenses L1 to L5 may beconfigured of a plastic lens, and any one surface or both surfaces ofeach of the first and fifth lenses L1 to L5 may be configured of anaspherical surface.

The reason why one or more surface of the lenses configuring the opticalsystem according to the exemplary embodiment of the present invention isconfigured of the aspherical surface is to minimize the sheet number oflenses capable of implementing a wide view angle, thereby configuringthe optical system for a camera that may be compactly manufactured tothereby be used in the mobile device. In addition, the reason why all ofthe first to fifth lenses L1 to L5 are configured of the plastic lens isto configure the optical system using the plastic lens capable of moreeasily manufacturing the aspherical surface lens as compared to theglass lens, thereby reducing a manufacturing cost and improving a degreeof freedom in design that may alleviate the chromatic aberrationcorrection and the manufacturing tolerance.

Meanwhile, as described above, in the optical system according to theexemplary embodiment of the present invention, the chromatic aberrationis corrected by the following Conditional Equations 1 and 2, the actingeffect of which will be described below.

f3/f<2.0  [Conditional Equation 1]

Where f3 indicates a focal length of the third lens, and f indicates afocal length of the entire optical system.

Conditional Equation 1 indicates a condition regarding the chromaticaberration correction of the optical system. In the case of being out ofan upper limit of Conditional Equation 1, focus adjusting positions foreach wavelength in the entire optical system become different, such thata phenomenon that a color of a photographed image is blurred may occur.

R31/f<1.2  [Conditional Equation 2]

Where R31 indicates a radius of curvature on a surface of the third lensL3 toward the object, and f indicates a focal length of the entireoptical system.

Conditional Equation 2 also indicates a condition regarding thechromatic aberration, similar to Conditional Equation 1. When thesurface of the first lens L1 toward the image is formed to be concave,the radius of curvature of the third lens L3 is increased, therebymaking it possible to correct the chromatic aberration. Here, in thecase of being out of an upper limit of Conditional Equation 2, since aback focal length (BFL) for each wavelength of the optical system may berapidly changed at a portion having a short wavelength, it is difficultto satisfy optical characteristics required in the present invention,that is, correction characteristics of the chromatic aberration.

Meanwhile, an aspherical surface used in the following exemplaryembodiments is obtained from the known Equation 1, and ‘E used in aConic constant (K) and aspherical surface coefficients (A, B, C, D, E,and F) and numerals next thereto’ indicate the power of 10. For example,E+02 indicates 10², and E-02 indicates 10⁻².

$\begin{matrix}{Z = {\frac{{cY}^{2}}{1 + \sqrt{1 - {\left( {1 + K} \right)c^{2}Y^{2}}}} + {AY}^{4} + {BY}^{6} + {CY}^{8} + {DY}^{10} + {EY}^{12} + {FY}^{14} + \ldots}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Where Z indicates a distance from the top of a lens in an optical axisdirection, Y indicates a distance in a direction vertical to an opticalaxis, c indicates a reciprocal number of a radius of curvature (r) atthe top of the lens, K indicates a Conic constant, and A, B, C, D, E,and F indicate aspherical surface coefficients.

First Exemplary Embodiment

The following Table 1 shows examples of numerical values according to afirst exemplary embodiment of the present invention.

In addition, FIG. 1 is a lens configuration diagram showing a lensarrangement of an optical system for a camera according to a firstexemplary embodiment of the present invention; and FIGS. 2A and 2B are,respectively, views showing astigmatism and distortion of the opticalsystem shown in Table 1 and FIG. 1.

In the case of the first exemplary embodiment, an effective focal length(f) of the entire optical system is 4.05 mm. In addition, all of thefirst to fifth lenses L1 to L5 are configured of an aspherical surfaceplastic lens.

Further, focal lengths of each lens used in the first exemplaryembodiment are as follows: f1=3.66 mm, f2=−3.80 mm, f3=5.09 mm, f4=2.27mm, and f5=−2.10 mm.

TABLE 1 Surface Radius of Thick- Refractive Abbe's Re- No. Curvature(R)ness (mm) Power (n) Number (v) marks *1 1.848 0.62 1.543 56.0 L1 *223.379 0.08 *3 6.605 0.36 1.635 23.7 L2 *4 1.729 0.18 *5 3.287 0.481.543 56.0 L3 *6 −16.575 0.52 *7 −2.149 0.72 1.543 56.0 L4 *8 −0.8770.15 *9 50.000 0.50 1.543 56.0 L5 *10 1.114 0.50 11 ∞ 0.30 1.517 64.2Optical 12 ∞ 0.69 Filter

In Table 1, a mark * before the surface number indicates an asphericalsurface. In the case of the first exemplary embodiment, both surfaces ofthe first to fifth lenses L1 to L5 are aspherical surfaces.

In addition, values of aspherical surface coefficients of the firstexemplary embodiment by Equation 1 are as shown by the following Table2.

TABLE 2 Surface No. K A B C D E 1 0.0000 0.0084 −0.0041 0.0154 −0.0025 —2 0.0000 −0.0191 0.0759 −0.0445 — — 3 0.0000 −0.1486 0.2118 −0.1457 — —4 0.0000 −0.2033 0.2187 −0.1079 −0.0016 — 5 0.0000 −0.0914 0.0289−0.0610 0.1737 −0.0957 6 0.0000 −0.0232 −0.0057 −0.0711 0.1253 −0.0467 70.0000 −0.0983 −0.0359 −0.0534 0.1083 −0.0121 8 −1.0000 0.2995 −0.55570.7744 −0.7865 0.5168 9 0.0000 −0.0941 −0.0209 0.0523 −0.0267 0.0058 10−7.4160 −0.0918 0.0364 −0.0124 0.0029 −0.0004

Second Exemplary Embodiment

The following Table 3 shows examples of numerical values according to asecond exemplary embodiment of the present invention.

In addition, FIG. 3 is a lens configuration diagram showing a lensarrangement of an optical system for a camera according to a secondexemplary embodiment of the present invention; and FIGS. 4A and 4B are,respectively, views showing astigmatism and distortion of the opticalsystem shown in Table 3 and FIG. 3.

In the case of the second exemplary embodiment, an effective focallength (f) of the entire optical system is 3.94 mm. In addition, all ofthe first to fifth lenses L1 to L5 are configured of an asphericalsurface plastic lens.

Further, focal lengths of each lens used in the second exemplaryembodiment are as follows: f1=3.68 mm, f2=−4.63 mm, f3=5.55 mm, f4=3.80mm, and f5=−2.51 mm.

TABLE 3 Surface Radius of Thick- Refractive Abbe's Re- No. Curvature(R)ness (mm) Power (n) Number (v) marks *1 1.858 0.63 1.543 56.0 L1 *222.800 0.08 *3 4.089 0.32 1.635 23.7 L2 *4 1.658 0.21 *5 4.173 0.591.543 56.0 L3 *6 −10.312 0.38 *7 −6.405 0.68 1.543 56.0 L4 *8 −1.6210.31 *9 22.423 0.50 1.543 56.0 L5 *10 1.275 0.50 11 ∞ 0.30 1.517 64.2Optical 12 ∞ 0.69 Filter

In Table 3, a mark * before the surface number indicates an asphericalsurface. In the case of the second exemplary embodiment, both surfacesof the first to fifth lenses L1 to L5 are aspherical surfaces.

In addition, values of aspherical surface coefficients of the secondexemplary embodiment by Equation 1 are as shown by the following Table4.

TABLE 4 Surface No. K A B C D E 1 0.0000 0.0084 −0.0021 0.0109 0.0057 —2 0.0000 −0.0456 0.1602 −0.0994 — — 3 0.0000 −0.2037 0.3035 −0.2414 — —4 0.0000 −0.2033 0.2528 −0.1822 0.0193 — 5 0.0000 −0.0538 0.0204 0.01210.0318 −0.0224 6 0.0000 −0.0377 −0.1047 0.1179 −0.1157 0.0569 7 0.00000.0272 −0.1782 0.2284 −0.2547 0.1598 8 −0.9827 0.0372 −0.0918 0.1788−0.2169 0.1592 9 0.0000 −0.4123 0.2687 −0.1214 0.0383 −0.0059 10 −7.4160−0.1583 0.0892 −0.0353 0.0085 −0.0012

Third Exemplary Embodiment

The following Table 5 shows examples of numerical values according to athird exemplary embodiment of the present invention.

In addition, FIG. 5 is a lens configuration diagram showing a lensarrangement of an optical system for a camera according to a thirdexemplary embodiment of the present invention; and FIGS. 6A and 6B are,respectively, views showing astigmatism and distortion of the opticalsystem shown in Table 5 and FIG. 5.

In the case of the third exemplary embodiment, an effective focal length(f) of the entire optical system is 4.10 mm. In addition, all of thefirst to fifth lenses L1 to L5 are configured of an aspherical surfaceplastic lens.

Further, focal lengths of each lens used in the third exemplaryembodiment are as follows: f1=3.694 mm, f2=−4.620 mm, f3=6.119 mm,f4=2.402 mm, and f5=−2.093 mm.

TABLE 5 Surface Radius of Thick- Refractive Abbe's Re- No. Curvature(R)ness (mm) Power (n) Number (v) marks *1 1.744 0.60 1.543 56.0 L1 *211.367 0.03 *3 10.729 0.35 1.635 23.7 L2 *4 2.292 0.25 *5 4.92 0.471.543 56.0 L3 *6 −10.035 0.57 *7 −2.048 0.60 1.543 56.0 L4 *8 −0.8820.08 *9 41.338 0.60 1.543 56.0 L5 *10 1.106 0.50 11 ∞ 0.30 1.517 64.2Optical 12 ∞ 0.70 Filter

In Table 5, a mark * before the surface number indicates an asphericalsurface. In the case of the third exemplary embodiment, both surfaces ofthe first to fifth lenses L1 to L5 are aspherical surfaces.

In addition, values of aspherical surface coefficients of the thirdexemplary embodiment by Equation 1 are as shown by the following Table6.

TABLE 6 Surface No. K A B C D E 1 0.0000 0.0078 0.0195 −0.0113 −0.0198 —2 0.0000 −0.0526 0.1366 −0.0815 — — 3 0.0000 −0.1764 0.2553 −0.1908 — —4 0.0000 −0.1762 0.2286 −0.1913 −0.0599 — 5 0.0000 −0.1167 0.0423−0.1200 0.1233 −0.0246 6 0.0000 −0.0608 −0.0169 −0.0400 0.0315 0.0061 70.0000 −0.0004 −0.0677 0.0671 −0.1283 0.1470 8 −1.0000 0.3049 −0.54330.7642 −0.7824 0.5108 9 0.0000 −0.0986 −0.0026 0.0286 −0.0168 0.0041 10−7.4160 −0.0864 0.0369 −0.0131 0.0029 −0.0004

Fourth Exemplary Embodiment

The following Table 7 shows examples of numerical values according to afourth exemplary embodiment of the present invention.

In addition, FIG. 7 is a lens configuration diagram showing a lensarrangement of an optical system for a camera according to a fourthexemplary embodiment of the present invention; and FIGS. 8A and 8B are,respectively, views showing astigmatism and distortion of the opticalsystem shown in Table 7 and FIG. 7.

In the case of the fourth exemplary embodiment, an effective focallength (f) of the entire optical system is 4.10 mm. In addition, all ofthe first to fifth lenses L1 to L5 are configured of an asphericalsurface plastic lens.

Further, focal lengths of each lens used in the fourth exemplaryembodiment are as follows: f1=3.959 mm, f2=−4.925 mm, f3=5.542 mm,f4=2.763 mm, and f5=−2.302 mm.

TABLE 7 Surface Radius of Thick- Refractive Abbe's Re- No. Curvature(R)ness (mm) Power (n) Number (v) marks *1 1.751 0.59 1.543 56.0 L1 *28.133 0.03 *3 7.962 0.35 1.635 23.7 L2 *4 2.222 0.25 *5 4.185 0.47 1.54356.0 L3 *6 −10.466 0.51 *7 −2.102 0.60 1.543 56.0 L4 *8 −0.966 0.10 *950.000 0.66 1.543 56.0 L5 *10 1.219 0.50 11 ∞ 0.30 1.517 64.2 Optical 12∞ 0.68 Filter

In Table 7, a mark * before the surface number indicates an asphericalsurface. In the case of the fourth exemplary embodiment, both surfacesof the first to fifth lenses L1 to L5 are aspherical surfaces.

In addition, values of aspherical surface coefficients of the fourthexemplary embodiment by Equation 1 are as shown by the following Table8.

TABLE 8 Surface No. K A B C D E 1 0.0000 0.0071 0.0183 −0.0097 −0.0185 —2 0.0000 −0.0854 0.1565 −0.0880 — — 3 0.0000 −0.2336 0.2973 −0.1993 — —4 0.0000 −0.2176 0.2534 −0.2119 0.0661 — 5 0.0000 −0.1155 −0.0049−0.0484 −0.0346 0.0635 6 0.0000 −0.0457 −0.0487 0.0103 −0.0496 0.0423 70.0000 −0.0409 −0.1167 0.2662 −0.2476 0.1189 8 −1.0000 0.1786 −0.20420.2245 −0.0938 0.0126 9 0.0000 −0.1691 0.1144 −0.0458 0.0083 0.0001 10−7.4160 −0.0995 0.0546 −0.0231 0.0062 −0.0010

Fifth Exemplary Embodiment

The following Table 9 shows examples of numerical values according to afifth exemplary embodiment of the present invention.

In addition, FIG. 9 is a lens configuration diagram showing a lensarrangement of an optical system for a camera according to a fifthexemplary embodiment of the present invention; and FIGS. 10A and 10Bare, respectively, views showing astigmatism and distortion of theoptical system shown in Table 9 and FIG. 9.

In the case of the fifth exemplary embodiment, an effective focal length(f) of the entire optical system is 4.16 mm. In addition, all of thefirst to fifth lenses L1 to L5 are configured of an aspherical surfaceplastic lens.

Further, focal lengths of each lens used in the fifth exemplaryembodiment are as follows: f1=3.749 mm, f2=−4.198 mm, f3=4.042 mm,f4=4.365 mm, and f5=−2.505 mm.

TABLE 9 Surface Radius of Thick- Refractive Abbe's Re- No. Curvature(R)ness (mm) Power (n) Number (v) marks *1 1.938 0.62 1.543 56.0 L1 *232.755 0.08 *3 −19.728 0.45 1.635 23.7 L2 *4 3.145 0.22 *5 4.193 0.561.543 56.0 L3 *6 −4.434 0.58 *7 −1.639 0.47 1.543 56.0 L4 *8 −1.069 0.23*9 44.872 0.70 1.543 56.0 L5 *10 1.319 0.50 11 ∞ 0.30 1.517 64.2 Optical12 ∞ 0.41 Filter

In Table 9, a mark * before the surface number indicates an asphericalsurface. In the case of the fifth exemplary embodiment, both surfaces ofthe first to fifth lenses L1 to L5 are aspherical surfaces.

In addition, values of aspherical surface coefficients of the fifthexemplary embodiment by Equation 1 are as shown by the following Table10.

TABLE 10 Surface No. K A B C D E 1 0.0000 0.0067 0.0161 −0.0043 −0.0121— 2 0.0000 −0.0246 0.0876 −0.0484 — — 3 0.0000 −0.1293 0.1672 −0.1329 —— 4 0.0000 −0.1654 0.1759 −0.1349 0.0344 — 5 0.0000 −0.0963 0.0301−0.0059 0.0170 −0.0053 6 0.0000 −0.0160 −0.0312 0.0119 0.0135 −0.0028 70.0000 0.0869 −0.1379 0.1153 −0.0644 0.0515 8 −1.0000 0.1292 −0.19150.2507 −0.2724 0.2071 9 0.0000 −0.1854 0.0877 −0.0323 0.0076 −0.0006 10−7.4160 −0.0813 0.0343 −0.0112 0.0022 −0.0002

Meanwhile, values of Conditional Equations 1 and 2 with respect to thefirst to fifth exemplary embodiments are as shown in Table 11.

TABLE 11 Exemplary Embodiment R31/f f3/f 1 0.811 1.255 2 1.059 1.408 31.200 1.492 4 1.020 1.351 5 1.007 0.971

As shown in the above Table 1, it may be confirmed that the first tofifth exemplary embodiments of the present invention satisfy ConditionalEquations 1 and 2.

As set forth above, in the optical system for a camera according to theexemplary embodiment of the present invention, five sheets of lenses areconfigured of the aspherical surface plastic lens, thereby making itpossible to decrease a manufacturing cost and implement a wide viewangle.

In addition, in the optical system for a camera according to theexemplary embodiment of the present invention, the third lens isconfigured to perform the chromatic aberration correction for the firstlens in a state in which five sheets of lenses are disposed, such thatthe first lens having the shape concave toward the image is used toalleviate the sensitivity to the manufacturing tolerance, thereby makingit possible to improve a degree of freedom in design.

Further, in the optical system for a camera according to the exemplaryembodiment of the present invention, the aperture stop is disposedbetween the first and second lenses, thereby making it possible toalleviate the sensitivity to the manufacturing tolerance of the firstlens and improve the ambient light amount ratio.

Although the exemplary embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims. Accordingly, suchmodifications, additions and substitutions should also be understood tofall within the scope of the present invention.

1-8. (canceled)
 9. An optical system, comprising a first lens havingpositive refractive power; a second lens having negative refractivepower and being concave toward an image side; a third lens being convextoward the image side; a fourth lens having positive refractive powerand comprising a meniscus shape being concave toward an object side andconvex toward the image side; a fifth lens having negative refractivepower and being concave in the center toward the image side, the fifthlens having at least one inflection point on an image-side surface and ashape being concave in the center toward the object side, wherein theoptical system satisfies the following conditional expression:${- 1.066} < \frac{f}{f\; 2} < {- 0.832}$ where f is a total focallength of the optical system, and f2 is a focal length of the secondlens, and wherein the first lens, the second lens, the third lens, thefourth lens and the fifth lenses are arranged in order from the objectside to the image side.
 10. The optical system of claim 9, wherein: thefirst lens is concave toward the image side and convex toward the objectside, and has a meniscus shape, and the fifth lens comprises an imageside surface being concave in the center and convex at the periphery.11. The optical system of claim 10, wherein each surface of the first,second, third, fourth and fifth lenses comprises an asperical surface,and the first, second, third, fourth and fifth lenses are made ofplastic.
 12. The optical system of claim 9, wherein the optical systemsatisfies the following conditional equation:f3/f<2.0 where f3 indicates a focal length of the third lens, and findicates a total length of the optical system.
 13. The optical systemof claim 12, wherein the optical system satisfies the followingconditional equation:R31/f<1.2 where R31 indicates a radius of curvature on an object-sidesurface of the third lens, and f indicates a total focal length of theoptical system.
 14. The optical system of claim 13, wherein abbe numbersof the first, fourth and fifth lenses are about
 56. 15. The opticalsystem of claim 14, wherein an abbe number of the second lens is about23.7.
 16. The optical system of claim 13, wherein the optical systemsatisfies the following conditional expression:d11>d31 where d11 is a thickness of the first lens, and d31 is athickness of the third lens.
 17. The optical system of claim 9, whereinthe optical system satisfies the following conditional expression:|R52/R42|>TTL/f where R52 is a radius of curvature of an image-sidesurface of the fifth lens, R42 is a radius of curvature of an image-sidesurface of the fourth lens, TTL is a distance on an optical axis from anobject-side surface of the first lens to an image lens, and f is anoverall focal distance of the optical system.
 18. The optical system ofclaim 9, wherein the optical system satisfies the following conditionalexpression:|R31+R32+R41+R42|>TTL where R31 is a radius of curvature of anobject-side surface of the third lens, R32 is a radius of curvature ofan image-side surface of the third lens, R41 is a radius of curvature ofan object-side surface of the fourth lens, R42 is a radius of curvatureof an image-side surface of the fourth lens, and TTL is a distance on anoptical axis from an object-side surface of the first lens to an imagelens.
 19. The optical system of claim 9, wherein the optical systemsatisfies the following conditional expression:−4.925≦f2≦−3.8 where f2 is a focal length of the second lens.
 20. Theoptical system of claim 19, wherein the optical system satisfies thefollowing conditional expression:2.27≦f4≦4.365 where f4 is a focal length of the fourth lens.
 21. Theoptical system of claim 9, wherein the optical system satisfies thefollowing conditional expression:$1.533 < \frac{r\; 7}{r\; 8} < 3.952$ where r7 is a radius ofcurvature of an object-side surface of the fourth lens, and r8 is aradius of curvature of an image-side surface of the fourth lens.
 22. Theoptical system of claim 9, wherein the optical system satisfies thefollowing conditional expression:$1.677 < \frac{{r\; 7} + {r\; 8}}{{r\; 7} - {r\; 8}} < 4.751$where r7 is a radius of curvature of an object-side surface of thefourth lens, and r8 is a radius of curvature of an image-side surface ofthe fourth lens.
 23. The optical system of claim 9, wherein the opticalsystem satisfies the following conditional expression:$0.033 < \frac{d\; 45}{f\; 4} < 0.082$ where d45 is a distance froman image-side surface of the fourth lens to an object-side surface ofthe fifth lens, and f4 is a focal length of the fourth lens.
 24. Theoptical system of claim 9, wherein the optical system satisfies thefollowing conditional expression:−6.405≦r7≦−1.639 where r7 is a radius of curvature of an object-sidesurface of the fourth lens.
 25. The optical system of claim 9, whereinthe optical system satisfies the following conditional expression:0.03≦d12≦0.080.38≦d34≦0.580.08≦d45≦0.31 where d12 is a distance from an image-side surface of thefirst lens to an object-side surface of the second lens, d34 is adistance from an image-side surface of the third lens to an object-sidesurface of the fourth lens, and d45 is a distance from an image-sidesurface of the fourth lens to an object-side surface of the fifth lens.26. The optical system of claim 9, wherein the optical system satisfiesthe following conditional expression:0.47≦ct4≦0.72 where ct4 is a thickness of the fourth lens.
 27. Theoptical system of claim 9, wherein the optical system satisfies thefollowing conditional expression:4.089≦|r3|≦19.7281.658≦r4≦3.1453.287≦|r5|≦4.92−1.621≦r8≦−0.877 where r3 is a radius of curvature of an object-sidesurface of the second lens, r4 is a radius of curvature of an image-sidesurface of the second lens, r5 is a radius of curvature of anobject-side surface of the third lens, and r8 is a radius of curvatureof an image-side surface of the fourth lens.
 28. The optical system ofclaim 9, wherein the optical system satisfies the following conditionalexpression:${- 1.959} < \frac{f}{f\; 5} < {{- 1.569} - 1.626} < \frac{r\; 7}{f} < {- 0.393}$$0.007 < \frac{d\; 12}{f\; 1} < 0.022$ where f is a total focallength of the optical system, f5 is a focal length of the fifth lens, r7is a radius of curvature of an object-side surface of the fourth lens,d12 is a distance from an image-side surface of the first lens to anobject-side surface of the second lens, and f1 is a focal length of thefourth lens.
 29. The optical system of claim 9, wherein the opticalsystem satisfies the following conditional expression:$1.037 < {\frac{r\; 3}{f}} < 4.743$$0.420 < \frac{r\; 4}{f} < 0.757$$0.811 < {\frac{r\; 5}{f}} \leq 1.2$ where r3 is a radius ofcurvature of an object-side surface of the second lens, r4 is a radiusof curvature of an image-side surface of the second lens, r5 is a radiusof curvature of an object-side surface of the third lens, and f is atotal focal length of the optical system.
 30. The optical system ofclaim 9, wherein the optical system satisfies the following conditionalexpression: $0.112 < \frac{{ct}\; 4}{f} < 0.178$$2.466 < {\frac{r\; 3}{r\; 4}} < 6.273$$0.198 < {\frac{r\; 5}{r\; 6}} < 0.946$ where ct4 is a thicknessof the fourth lens, f is a focal length of the optical system, r3 is aradius of curvature of an object-side surface of the second lens, and r4is a radius of curvature of an image-side surface of the second lens, r5is a radius of curvature of an object-side surface of the third lens,and r6 is a radius of curvature of an image-side surface of the thirdlens.
 31. The optical system of claim 9, wherein the optical systemsatisfies the following conditional expression:$0.725 < \frac{{r\; 3} + {r\; 4}}{{r\; 3} - {r\; 4}} < 2.365$where r3 is a radius of curvature of an object-side surface of thesecond lens, and r4 is a radius of curvature of an image-side surface ofthe second lens.
 32. The optical system of claim 9, wherein the opticalsystem satisfies the following conditional expression:$0.007 < \frac{d\; 12}{f} < 0.021$$0.096 < \frac{d\; 34}{f} < 0.140$$0.019 < \frac{d\; 45}{f} < 0.079$ where d12 is a distance from animage-side surface of the first lens to an object-side surface of thesecond lens, d34 is a distance from an image-side surface of the thirdlens to an object-side surface of the fourth lens, d45 is a distancefrom an image-side surface of the fourth lens to an object-side surfaceof the fifth lens, and f is a total focal distance of the opticalsystem.
 33. The optical system of claim 9, wherein the optical systemsatisfies the following conditional expression:$0.291 < \frac{d\left( {{S\; 4} - {S\; 8}} \right)}{f} < 0.327$where d(S4-S8) is a distance on an optical axis from an image-sidesurface S4 of the second lens to an object-side surface S8 of the fourthlens, and f is a total focal length of the optical system.
 34. Anoptical system, comprising: a first lens having positive refractivepower and comprising a meniscus shape being convex toward an objectside; a second lens having negative refractive power and comprising aconcave surface on an image side; a third lens comprising a convexsurface on the image side; a fourth lens having positive refractivepower and comprising a meniscus shape being concave toward the objectside and convex toward the image side; a fifth lens having negativerefractive power and comprising: an image-side surface being concave inthe center and convex at the periphery and having at least oneinflection point thereon; and an object-side surface being concavetoward the object side, wherein: the optical system satisfies thefollowing conditional expression:${- 1.066} < \frac{f}{f\; 2} < {- 0.832}$ where f is a total focallength of the optical system, and f2 is a focal length of the secondlens, the first lens, the second lens, the third lens, the fourth lensand the fifth lenses are arranged in order from the object side to theimage side, and the meniscus shape of the first and fourth lenses, theconcave surface of the second lens and the convex surface of the thirdlens are arranged on an optical axis.
 35. The optical system of claim34, wherein the optical system satisfies the following conditionalexpression:−4.925≦f2≦−3.82.27≦f4≦4.365−6.405≦r7≦−1.639 where f2 is a focal length of the second lens, and f4is a focal length of the fourth lens, and r7 is a radius of curvature ofan object-side surface of the fourth lens.
 36. The optical system ofclaim 35, wherein the optical system satisfies the following conditionalexpression:0.47≦ct4≦0.720.03≦d12≦0.080.38≦d34≦0.580.08≦d45≦0.31 where ct4 is a thickness of the fourth lens, d12 is adistance from an image-side surface of the first lens to an object-sidesurface of the second lens, d34 is a distance from an image-side surfaceof the third lens to an object-side surface of the fourth lens, and d45is a distance from an image-side surface of the fourth lens to anobject-side surface of the fifth lens.
 37. The optical system of claim35, wherein the optical system satisfies the following conditionalexpression:1.658≦r4≦3.145−1.621≦r8≦−0.877 where r4 is a radius of curvature of an image-sidesurface of the second lens, and r8 is a radius of curvature of animage-side surface of the fourth lens.
 38. The optical system of claim37, wherein the optical system satisfies the following conditionalexpression: $1.533 < \frac{r\; 7}{r\; 8} < 3.952$ where r7 is aradius of curvature of an object-side surface of the fourth lens, and r8is a radius of curvature of an image-side surface of the fourth lens.